The present invention relates to a modular, lightweight, non-corrosive, easy to construct storage rack or shelving unit. The storage rack is designed to be used for the storage of corrosive products such as liquid chemicals. The storage of such products inherently demands a shelving unit which is structurally strong, and not affected by the corrosive action of the stored products. Further, the shelving unit should provide easy access to the products stored. Further, it is desirable that the storage rack be lightweight and easy to assemble and disassemble for the purposes of cleaning the storage site. In the past, various combinations of metal shelving have been used for such storage and have been found to be unsatisfactory in providing the safe, clean chemical storage desired.